1. Field of the Invention
The present invention relates to a method of producing a liquid seasoning. In particular, it relates to a method of producing a novel, high quality liquid seasoning from cheese whey (hereinafter referred to as whey). Whey is produced in large quantities in the production of cheese all over the world and has not been fully utilized.
2. Discussion of the Background
The amount of cheese produced in the world is far greater than 10 million tons per year. In the production of cheese, nearly 90 million tons of whey is produced. However, techniques for utilizing whey have not been well developed. In the United States, where cheese is produced on a comparatively large scale, nearly half of the whey produced is considered a waste product requiring treatment at a considerable cost in order to prevent the pollution of water.
Even in the United States in which cheese is produced in factories on a relatively large scale, and hence the whey can be processed economically, only about 1.4 million tons (as solids) of whey is processed commercially. This is less than 50% of the total amount of whey produced from cheese factories.
Moreover, 75% of the processing is a simple condensation or drying, and 14% of the processing is the conversion of whey into lactose according to traditional processes, wherein proteins contained in whey are precipitated and removed, and the remaining liquid is merely subjected to a condensation or drying.
Whey is also processed into a whey protein concentrate (hereinafter referred to as WPC), employing the technology of ultrafiltration. This is applied to only 9% of the commercially processed whey, however.
As described above, the primary reason why techniques for utilizing whey have not been well developed lies in the fact that whey is of limited value when utilized for food. To be more specific, the use of whey is limited only to excipients, etc., in the food industry. In reality, even the use of WPC, which is processed to a relatively high extent, does not go beyond a substitute for skim milk. From a technical point of view, the solids content of whey is quite low, i.e., only 6.5% on the average. The solids content of whey consists of 70% by weight lactose, 10% by weight proteins and 20% by weight inorganic salts. Of these components, proteins are not heat stable and, once thermally denatured, become insoluble in water or a solution of salts, which reduces the utility value of the whey.
As described above, organic salts are present in whey in relatively large quantities. Among the salts contained in whey are cations, such as potassium, sodium, calcium and magnesium ions; and anions, such as chloride and phosphate ions. Because of the presence of large quantities of inorganic salts, whey has to be subjected to a desalting procedure before being utilized, which further decreases the utility value of whey.
In the production of WPC, proteins are condensed without being denatured by means of ultrafiltration, thus making it possible to solve the above-described disadvantages of whey. However, a need remains for a method of utilizing lactose and the inorganic salt fractions produced as by-products. This also restricts the production of WPC. There exists a substantial need to develop new techniques for utilizing whey. The present invention is directed to a new method for utilizing whey.